High-entropy alloy binder phase gradient cemented carbide tool material and method for manufacturing same

Abstract

This invention belongs to the field of cemented carbide materials technology, and specifically relates to a high-entropy alloy binder phase gradient cemented carbide tool material and its preparation method. This invention uses a high-entropy alloy as a Co-binding phase in the cemented carbide, and introduces nano-ZrO. 2 To achieve phase transformation toughening, a graphene gradient (with decreasing content from the surface inwards) is introduced as a stable phase in the binder phase during liquid-phase sintering. Silicon carbide nanowires are introduced on the surface as a graphene dispersed phase, significantly improving the densification of WC materials. Carbon nanotubes are introduced in the transition layer as a graphene dispersed phase, coupling the atomic topological disorder of high-entropy alloys with the macro-micro ordered phase of the graphene gradient structure. The controllable distribution and preferred orientation of graphene are correlated with the gradient structure evolution of the high-entropy alloy binder phase cemented carbide. Through two-step liquid-phase + solid-phase sintering, a high-hardness, high-strength, high-toughness high-entropy alloy binder phase gradient cemented carbide tool material is obtained.

Description

A high-entropy alloy binder phase gradient cemented carbide tool material and its preparation method Technical Field

[0001] This invention belongs to the field of cemented carbide materials technology, and specifically relates to a high-entropy alloy binder phase gradient cemented carbide tool material and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Carbide cutting tools dominate the cutting tool market, accounting for as much as 70%. In particular, over 90% of turning tools and over 55% of end mills in developed countries are made of carbide materials. However, the metallic properties of the binder phase (mainly Co) and the "macroscopically homogeneous" structure of traditional carbide tools result in a contradiction between hardness and toughness, as well as insufficient wear resistance and chemical stability, making it difficult to adapt to the multi-field coupling and interaction of thermo-mechanical-chemical processes in high-speed cutting. Research on Co-replacement binder phases has gone through four stages. Among them, metal-based Co-replacement binder phases (such as Fe, Ni, etc.) in carbide cutting tools exhibit insufficient hardness, wear resistance, corrosion resistance, and oxidation resistance. Meanwhile, intermetallic compound (such as FeAl, Ni3Al, etc.) and ceramic binder phase (Al2O3, TiC, etc.) carbides have poor strength and toughness. High-entropy alloys have broken through the bottleneck of traditional material design, exhibiting high stability and flexibility in microstructure control and the ability to achieve a combination of various excellent properties. They are the most promising Co-replacement binder phases, and related research is just beginning.

[0004] Gradient-function carbide tool materials achieve optimal overall performance configuration through rational tailoring and splicing of components and structures, thereby improving the adaptability and resistance of gradient-function carbide tools to non-uniform multi-field coupling and interaction in high-speed cutting. The preparation methods of gradient-function carbide have been continuously developing with the advancement of new sintering technologies and sintering thermodynamics and kinetics. However, existing processes are relatively complex. For example, solid-state sintering requires subsequent hot isostatic pressing to eliminate residual porosity in the sintered body; while controlled atmosphere sintering requires the preparation of carbide billets with abnormal carbon or nitrogen content. In summary, liquid-phase sintering is a feasible option for the industrial production of gradient-function carbide, but research on how to prevent the disappearance of the pre-designed binder phase gradient during liquid-phase sintering is lacking.

[0005] The inventor's previous patent CN116732405A disclosed a cutting tool material containing a gradient high-entropy cemented carbide and its preparation method. The surface layer includes high-entropy carbide, high-entropy alloy, and graphene; the transition layer includes high-entropy carbide, high-entropy alloy, and WC hard phase; and the core layer includes high-entropy alloy and WC hard phase. However, since it is a high-entropy cemented carbide, it does not address how to prepare the high-entropy alloy binder phase cemented carbide. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a high-hardness, high-strength, high-toughness high-entropy alloy binder phase gradient cemented carbide tool material, and also provides a simple preparation method suitable for industrial production.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a high-entropy alloy binder phase gradient cemented carbide tool material, comprising:

[0009] The layers are arranged from top to bottom as follows: upper surface layer, first transition layer, core layer, second transition layer, and lower surface layer.

[0010] The upper and lower surface layers have the same composition, consisting of the following raw materials in parts by weight: 98.9-99.5 parts WC, 0.2-0.5 parts high-entropy alloy, 0.1-0.2 parts graphene, and 0.2-0.4 parts silicon carbide nanowires;

[0011] The first transition layer and the second transition layer have the same composition, consisting of the following raw materials in parts by weight: 84.7 to 91.85 parts WC, 5 to 10 parts high-entropy alloy, 3 to 5 parts ZrO2, 0.05 to 0.1 parts graphene, and 0.1 to 0.2 parts carbon nanotubes;

[0012] The core layer is composed of the following raw materials in parts by weight: 96.85-94.7 parts WC, 10-15 parts high-entropy alloy, and 5-7 parts ZrO.

[0013] This invention introduces a high-entropy alloy as a binder phase to replace Co in cemented carbide, introduces nano-ZrO2 to achieve phase transformation strengthening and toughening, introduces a graphene gradient (with decreasing content from the surface to the interior) as a gradient stabilizing phase in the liquid-phase sintering process, introduces silicon carbide nanowires as a graphene dispersion phase in the surface layer to significantly improve the densification of WC materials, and introduces carbon nanotubes as a graphene dispersion phase in the transition layer. This couples the microscale disorder of the high-entropy alloy with the macroscale ordered phase of the gradient structure, and links the controllable distribution and preferred orientation of graphene with the gradient structure evolution of the high-entropy alloy binder phase cemented carbide. Through a two-step liquid-phase + solid-phase sintering process, a high-hardness, high-strength and high-toughness high-entropy alloy binder phase gradient cemented carbide tool material is obtained.

[0014] In some embodiments, the high-entropy alloy is composed of any five elements selected from Fe, Co, Ni, Cr, Mn, and Al.

[0015] A second aspect of the present invention provides a method for preparing a high-entropy alloy binder phase gradient cemented carbide tool material, comprising:

[0016] Five metal powders from Fe, Co, Ni, Cr, Mn and Al were weighed in equal molar ratio, and metal suspensions were prepared separately. The suspensions were mixed evenly, wet ball milled, and dried to obtain a high-entropy alloy.

[0017] Graphene, carbon nanotubes, silicon carbide nanowires, and nano ZrO2 were respectively prepared into suspensions;

[0018] According to the composition of each gradient layer, WC powder and high-entropy alloy powder were respectively mixed with nanophase suspension to obtain powder suspensions of each gradient layer. They were then wet ball-milled and dried to obtain powders of each gradient layer.

[0019] The powder is loaded using a layered pressing method, and five layers of gradient powder are pressed into shape. The powder is then sintered using a two-step liquid-phase + solid-phase discharge plasma sintering process.

[0020] In some embodiments, the metal suspension uses anhydrous ethanol as the dispersion solvent and polyethylene glycol as the dispersion medium.

[0021] In some embodiments, the metal suspension is ultrasonically dispersed in a water bath at 100–105°C for 1–2 hours.

[0022] In some embodiments, a complex dispersant comprising 80% to 85% of the mass of the graphene, carbon nanotubes, or silicon carbide nanowires is added to the suspension of the graphene, carbon nanotubes, or silicon carbide nanowires.

[0023] In some embodiments, the compound dispersant is composed of polyethylene glycol and polyvinylpyrrolidone in a ratio of 1:1 to 1.5.

[0024] In some embodiments, the suspension of nano-ZrO2 is prepared by using anhydrous ethanol as the dispersion solvent and adding 1.0% to 1.5% polyethylene glycol relative to the mass of the nano-ZrO2 particles.

[0025] In some embodiments, the specific conditions of the liquid phase + solid phase two-step discharge plasma sintering process are as follows: the vacuum degree is maintained below 10 Pa, the temperature is increased to 1400-1450℃ at 150℃ / min, held for 1-5 min, then cooled to 1250-1300℃ at 150℃ / min, held for 1-6 h, and then cooled with the furnace; the pressure is maintained at 20 MPa from room temperature to 1200℃, and at 45 MPa from 1200-1250 to 1450℃.

[0026] Specifically, the following steps are included:

[0027] (1) Preparation of high-entropy alloy powder

[0028] Five metal powders (any five of Fe, Co, Ni, Cr, Mn, and Al) were weighed in equimolar ratios. Anhydrous ethanol was used as the dispersion solvent, and polyethylene glycol as the dispersion medium. The five metal suspensions were prepared separately and ultrasonically dispersed in a water bath at 100°C for 1 hour. Under mechanical stirring and ultrasonic dispersion, the five metal suspensions were mixed to obtain a high-entropy alloy suspension, which was then ultrasonically dispersed for another 1 hour. Grinding balls were added at a specific ball-to-powder ratio, and the mixture was ball-milled for 24 hours. The powder was then dried in a vacuum drying oven and sieved to obtain the high-entropy alloy powder.

[0029] (2) Ingredients

[0030] The surface layer is composed of (98.9~99.5)WC-(0.2~0.5)high-entropy alloy-(0.1~0.2)graphene-(0.2~0.4)silicon carbide nanowires by mass ratio; the transition layer is composed of (84.7~91.85)WC-(5~10)high-entropy alloy-(3~5)ZrO2-(0.05~0.1)graphene-(0.1~0.2)carbon nanotubes by mass ratio; and the core layer is composed of (96.85~94.7)WC-(10~15)high-entropy alloy-(5~7)ZrO2 by mass ratio.

[0031] (3) Nanophase dispersion

[0032] Graphene, carbon nanotubes, and silicon carbide nanowires were dispersed using anhydrous ethanol as the dispersion solvent. A compound dispersant (polyethylene glycol: polyvinylpyrrolidone = 1:1) of 80% relative to the mass of graphene, carbon nanotubes, and silicon carbide nanowires was added to prepare a suspension, which was then ultrasonically dispersed in a water bath at 100°C for 60 min.

[0033] The nano-ZrO2 was dispersed using anhydrous ethanol as the dispersion solvent, and 1.0% polyethylene glycol (based on the relative mass of the nano-ZrO2 particles) was added to prepare a suspension. The suspension was then ultrasonically dispersed in a water bath at 100°C for 30 minutes.

[0034] (4) Mixing

[0035] According to the proportions in step (2), WC powder and high-entropy alloy powder are mixed with the nanophase suspension prepared in step (3), and ultrasonically dispersed in a water bath at 100°C for 30 min to obtain powder suspensions of each gradient layer. Grinding balls are added at a certain ball-to-material ratio, and the mixture is ball-milled for 30 h. Then, it is dried in a vacuum drying oven and sieved to obtain well-dispersed powders of each gradient layer.

[0036] (5) Pressing and sintering

[0037] The weight of powder in each gradient layer was calculated based on the mold size and gradient layer thickness. The five gradient powder layers were pressed into shape using a layered pressing method. A two-step discharge plasma sintering process of liquid phase + solid phase was adopted: the vacuum degree was maintained below 10 Pa, the temperature was increased to 1400-1450℃ at 150℃ / min, held for 1-5 min, and then cooled to 1250-1300℃ at 150℃ / min, held for 1-6 h, and then cooled in the furnace. The pressure was maintained at 20 MPa from room temperature to 1200℃, and at 45 MPa from 1200-1250 to 1450℃.

[0038] The above process continues until the sintering process is completed, at which point a high-hardness, high-strength, high-toughness, high-entropy alloy binder phase gradient cemented carbide tool material can be obtained.

[0039] A third aspect of the present invention provides the high-entropy alloy binder phase gradient cemented carbide tool material described above, and the application of the high-entropy alloy binder phase gradient cemented carbide tool material prepared by any of the above methods in the preparation of cemented carbide tools.

[0040] Beneficial effects of the present invention

[0041] (1) This invention introduces a high-entropy alloy as a Co binder phase and adopts a liquid phase + solid phase two-step sintering process. Without the need to add grain growth inhibitors, high densification can be achieved while suppressing the grain growth of cemented carbide.

[0042] (2) Compared with homogeneous materials formed by liquid phase migration along gradient direction that cannot be prevented during sintering, the present invention introduces graphene into the surface layer and transition layer. The migration of liquid phase high-entropy alloy along gradient direction can be suppressed by the orientation distribution of graphene, and the integrity of the pre-designed high-entropy alloy gradient can be maintained to the maximum extent during sintering.

[0043] (3) The present invention introduces silicon carbide nanowires as a graphene dispersion phase on the surface layer, which significantly improves the densification of the material while effectively suppressing graphene agglomeration.

[0044] (4) From a production technology perspective, a technology is provided for the industrial production of high-hardness, high-strength, high-entropy alloy bonded phase gradient cemented carbide tool materials.

[0045] (5) Compared with patent CN116732405A, this invention introduces one-dimensional carbon nanomaterials (carbon nanotubes and silicon carbide nanowires), which can significantly inhibit the agglomeration of graphene inside the tool material and promote the densification of the tool material, thus significantly improving the bending strength of the tool. At the same time, this invention introduces nano-zirconia, which plays a role in phase transformation toughening and internal crystal toughening, significantly improving the strength and toughness of the tool material. In addition, through the gradient change of ZrO2, residual compressive stress can be introduced into the surface layer, which can significantly improve the strength, toughness and hardness of the tool material. Furthermore, the surface layer of this invention contains less than 0.5% high-entropy alloy by mass, and the surface layer is actually a cemented carbide without a binder phase, which can significantly improve the overall wear resistance of the material. Finally, the wettability of high-entropy alloy to WC is better than that of high-entropy alloy to high-entropy carbide, so the material of this invention is easier to achieve high / complete densification.

[0046] (6) The preparation method of the present invention is simple, practical and easy to promote. Detailed Implementation

[0047] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0048] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0049] In the following examples, in step (1), the amount of dispersion medium (polyethylene glycol) added is 0.3% of the total mass of the metal powder.

[0050] Example 1

[0051] (1) Using five metal powders (0.5 μm Fe, Co, Ni, Cr, and Al) as raw materials, they were prepared in equimolar ratios. Anhydrous ethanol was used as the dispersion solvent and polyethylene glycol as the dispersion medium to prepare suspensions of the five metals, which were then ultrasonically dispersed in a water bath at 100°C for 1 hour. Under mechanical stirring and ultrasonic dispersion, the five metal suspensions were mixed to obtain a high-entropy alloy suspension, which was then ultrasonically dispersed for another 1 hour. Grinding balls were added at a certain ball-to-material ratio, and the mixture was ball-milled for 24 hours. The mixture was then dried in a vacuum drying oven and sieved to obtain a well-dispersed high-entropy alloy binder phase powder.

[0052] (2) Using the high-entropy alloy, 0.4μm tungsten carbide (WC), 100nm zirconium oxide (ZrO2), graphene, carbon nanotubes, and silicon carbide nanowires from step (1) as raw materials, the surface layer is formulated with a mass ratio of 99.35WC-0.2 high-entropy alloy-0.15 graphene-0.3 silicon carbide nanowires, the transition layer with a mass ratio of 91.85WC-5 high-entropy alloy-3ZrO2-0.05 graphene-0.1 carbon nanotubes, and the core layer with a mass ratio of 85WC-10 high-entropy alloy.

[0053] -5ZrO2 mass ratio.

[0054] (3) Graphene, carbon nanotubes, and silicon carbide nanowires were dispersed using anhydrous ethanol as the dispersion solvent, with 80% (by weight) of a compound dispersant (polyethylene glycol) added relative to the mass of graphene, carbon nanotubes, and silicon carbide nanowires.

[0055] Polyvinylpyrrolidone (1:1) was prepared into a suspension and ultrasonically dispersed in a water bath at 100°C for 60 min.

[0056] The nano-ZrO2 was dispersed using anhydrous ethanol as the dispersion solvent, and 1.0% polyethylene glycol (based on the relative mass of the nano-ZrO2 particles) was added to prepare a suspension. The suspension was then ultrasonically dispersed in a water bath at 100°C for 30 minutes.

[0057] (4) According to the proportions in step (2), WC powder and high-entropy alloy powder are mixed with the nanophase suspension prepared in step (3), and ultrasonically dispersed in a water bath at 100°C for 30 min to obtain powder suspensions of each gradient layer. Grinding balls are added at a certain ball-to-material ratio, and the mixture is ball-milled for 30 h. Then it is dried in a vacuum drying oven and sieved to obtain well-dispersed powders of each gradient layer.

[0058] (5) The liquid phase + solid phase two-step discharge plasma sintering process is adopted: the vacuum degree is kept below 10 Pa, the temperature is raised to 1450℃ at 150℃ / min, held for 5 min, then cooled to 1300℃ at 150℃ / min and held for 1 h, and then cooled with the furnace; the pressure is kept at 20 MPa from room temperature to 1200℃, and the pressure is kept at 45 MPa from 1200-1450℃.

[0059] The above process, from start to finish, yields a high-hardness, high-strength, high-entropy alloy binder phase gradient cemented carbide tool material. Its mechanical properties are: Vickers hardness HV. 30 23.8 GPa, flexural strength 1967.1 MPa, fracture toughness 13.9 MPa·m 1 / 2 .

[0060] Example 2

[0061] (1) Using five metal powders (0.5 μm Fe, Ni, Cr, Mn, and Al) as raw materials, they were prepared in equimolar ratios. Anhydrous ethanol was used as the dispersion solvent and polyethylene glycol as the dispersion medium to prepare suspensions of the five metals, which were then ultrasonically dispersed in a water bath at 100°C for 1 hour. Under mechanical stirring and ultrasonic dispersion, the five metal suspensions were mixed to obtain a high-entropy alloy suspension, which was then ultrasonically dispersed for another 1 hour. Grinding balls were added at a certain ball-to-material ratio, and the mixture was ball-milled for 24 hours. The mixture was then dried in a vacuum drying oven and sieved to obtain a well-dispersed high-entropy alloy binder phase powder.

[0062] (2) Using the high-entropy alloy, 0.4μm tungsten carbide (WC), 100nm zirconium oxide (ZrO2), graphene, carbon nanotubes and silicon carbide nanowires from step (1) as raw materials, the surface layer is formulated with a mass ratio of 99.4WC-0.3 high-entropy alloy-0.1 graphene-0.2 silicon carbide nanowires, the transition layer is formulated with a mass ratio of 91.7WC-5 high-entropy alloy-3ZrO2-0.1 graphene-0.2 carbon nanotubes, and the core layer is formulated with a mass ratio of 85WC-10 high-entropy alloy-5ZrO2.

[0063] (3) Graphene, carbon nanotubes, and silicon carbide nanowires were dispersed using anhydrous ethanol as the dispersion solvent, with 80% (by weight) of a compound dispersant (polyethylene glycol) added relative to the mass of graphene, carbon nanotubes, and silicon carbide nanowires.

[0064] Polyvinylpyrrolidone (1:1) was prepared into a suspension and ultrasonically dispersed in a water bath at 100°C for 60 min.

[0065] The nano-ZrO2 was dispersed using anhydrous ethanol as the dispersion solvent, and 1.0% polyethylene glycol (based on the relative mass of the nano-ZrO2 particles) was added to prepare a suspension. The suspension was then ultrasonically dispersed in a water bath at 100°C for 30 minutes.

[0066] (4) According to the proportions in step (2), WC powder and high-entropy alloy powder are mixed with the nanophase suspension prepared in step (3), and ultrasonically dispersed in a water bath at 100°C for 30 min to obtain powder suspensions of each gradient layer. Grinding balls are added at a certain ball-to-material ratio, and the mixture is ball-milled for 30 h. Then it is dried in a vacuum drying oven and sieved to obtain well-dispersed powders of each gradient layer.

[0067] (5) The liquid phase + solid phase two-step discharge plasma sintering process is adopted: the vacuum degree is kept below 10 Pa, the temperature is raised to 1425℃ at 150℃ / min, held for 5 min, then cooled to 1300℃ at 150℃ / min and held for 1 h, and then cooled with the furnace; the pressure is kept at 20 MPa from room temperature to 1200℃, and the pressure is kept at 45 MPa from 1200 to 1425℃.

[0068] The above process, from start to finish, yields a high-hardness, high-strength, high-entropy alloy binder phase gradient cemented carbide tool material. Its mechanical properties are: Vickers hardness HV. 30 24.1 GPa, flexural strength 2072.2 MPa, fracture toughness 13.5 MPa·m 1 / 2 .

[0069] Example 3

[0070] (1) Using five metal powders (0.5 μm Fe, Co, Ni, Cr, and Mn) as raw materials, they were prepared in equimolar ratios. Anhydrous ethanol was used as the dispersion solvent and polyethylene glycol as the dispersion medium to prepare suspensions of the five metals, which were then ultrasonically dispersed in a water bath at 100°C for 1 hour. Under mechanical stirring and ultrasonic dispersion, the five metal suspensions were mixed to obtain a high-entropy alloy suspension, which was then ultrasonically dispersed for another 1 hour. Grinding balls were added at a certain ball-to-material ratio, and the mixture was ball-milled for 24 hours. The powder was then dried in a vacuum drying oven and sieved to obtain a well-dispersed high-entropy alloy binder phase powder.

[0071] (2) Using the high-entropy alloy, 0.4μm tungsten carbide (WC), 100nm zirconium oxide (ZrO2), graphene, carbon nanotubes and silicon carbide nanowires from step (1) as raw materials, the surface layer is formulated with a mass ratio of 99.25WC-0.3 high-entropy alloy-0.15 graphene-0.3 silicon carbide nanowires, the transition layer is formulated with a mass ratio of 91.7WC-5 high-entropy alloy-3ZrO2-0.1 graphene-0.2 carbon nanotubes, and the core layer is formulated with a mass ratio of 85WC-10 high-entropy alloy-5ZrO2.

[0072] (3) Graphene, carbon nanotubes, and silicon carbide nanowires were dispersed using anhydrous ethanol as the dispersion solvent, with 80% (by weight) of a compound dispersant (polyethylene glycol) added relative to the mass of graphene, carbon nanotubes, and silicon carbide nanowires.

[0073] A suspension was prepared using polyvinylpyrrolidone (1:1), and ultrasonically dispersed in a 100°C water bath for 60 min. For the dispersion of nano-ZrO2, anhydrous ethanol was used as the dispersion solvent, and the amount added was determined based on the relative mass of the nano-ZrO2 particles.

[0074] A suspension of 1.0% polyethylene glycol was prepared and ultrasonically dispersed in a water bath at 100°C for 30 minutes.

[0075] (4) According to the proportions in step (2), WC powder and high-entropy alloy powder are mixed with the nanophase suspension prepared in step (3), and ultrasonically dispersed in a water bath at 100°C for 30 min to obtain powder suspensions of each gradient layer. Grinding balls are added at a certain ball-to-material ratio, and the mixture is ball-milled for 30 h. Then it is dried in a vacuum drying oven and sieved to obtain well-dispersed powders of each gradient layer.

[0076] (5) The liquid phase + solid phase two-step discharge plasma sintering process is adopted: the vacuum degree is kept below 10 Pa, the temperature is raised to 1450℃ at 150℃ / min, held for 5 min, then cooled to 1300℃ at 150℃ / min and held for 1 h, and then cooled with the furnace; the pressure is kept at 20 MPa from room temperature to 1200℃, and the pressure is kept at 45 MPa from 1200-1450℃.

[0077] The above process, from start to finish, yields a high-hardness, high-strength, high-entropy alloy binder phase gradient cemented carbide tool material. Its mechanical properties are: Vickers hardness HV. 30 23.6 GPa, flexural strength 1921.1 MPa, fracture toughness 12.9 MPa·m 1 / 2 .

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-entropy alloy binder phase gradient cemented carbide tool material, characterized in that, include: The layers are arranged from top to bottom as follows: upper surface layer, first transition layer, core layer, second transition layer, and lower surface layer. The upper and lower surface layers have the same composition, consisting of the following raw materials in parts by weight: WC 98.9~99.5 parts, high-entropy alloy 0.2~0.5 parts, graphene 0.1~0.2 parts, and silicon carbide nanowires 0.2~0.4 parts; the first and second transition layers have the same composition, consisting of the following raw materials in parts by weight: WC 84.7~91.85 parts, high-entropy alloy 5~10 parts, ZrO2 3~5 parts, graphene 0.05~0.1 parts, and carbon nanotubes 0.1~0.2 parts; the core layer consists of the following raw materials in parts by weight: WC 96.85~94.7 parts, high-entropy alloy 10~15 parts, ZrO2 5~7 parts; wherein, the content gradient of graphene decreases from the surface to the interior, serving as a gradient stabilizing phase to suppress the migration of the high-entropy alloy binder phase along the gradient direction during liquid phase sintering; the content gradient of ZrO2 increases from the surface to the interior, which can introduce residual compressive stress into the surface layer.

2. The high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 1, characterized in that, The high-entropy alloy is composed of any five elements selected from Fe, Co, Ni, Cr, Mn, and Al.

3. A method for preparing a high-entropy alloy binder phase gradient cemented carbide tool material, characterized in that, include: Five metal powders from Fe, Co, Ni, Cr, Mn, and Al were weighed in equimolar ratio, and metal suspensions were prepared separately. The suspensions were mixed evenly, wet ball milled, and dried to obtain a high-entropy alloy. Graphene, carbon nanotubes, silicon carbide nanowires, and nano ZrO2 were prepared separately into suspensions. According to the composition of each gradient layer in claim 1 or 2, WC powder and high-entropy alloy powder are respectively mixed with nanophase suspension to obtain each gradient layer powder suspension, wet ball milling, drying to obtain each gradient layer powder; the five gradient powder layers are pressed into shape using a layered pressing method, and then sintered by liquid phase + solid phase two-step discharge plasma sintering to obtain the final product.

4. The method for preparing high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 3, characterized in that, The metal suspension uses anhydrous ethanol as the dispersion solvent and polyethylene glycol as the dispersion medium.

5. The method for preparing high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 3, characterized in that, The metal suspension was ultrasonically dispersed in a water bath at 100-105°C for 1-2 hours.

6. The method for preparing high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 3, characterized in that, A complex dispersant, comprising 80% to 85% of the mass of graphene, carbon nanotubes, or silicon carbide nanowires, is added to the suspension of graphene, carbon nanotubes, or silicon carbide nanowires.

7. The method for preparing high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 6, characterized in that, The compound dispersant is composed of polyethylene glycol and polyvinylpyrrolidone in a ratio of 1:1 to 1.

5.

8. The method for preparing high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 3, characterized in that, The suspension of nano-ZrO2 was prepared by using anhydrous ethanol as the dispersion solvent and adding 1.0% to 1.5% polyethylene glycol relative to the mass of the nano-ZrO2 particles.

9. The method for preparing high-entropy alloy binder phase gradient cemented carbide tool material as described in claim 3, characterized in that, The specific conditions for the liquid-phase + solid-phase two-step discharge plasma sintering process are as follows: the vacuum degree is maintained below 10 Pa, the temperature is increased to 1400-1450℃ at 150℃ / min, held for 1-5 min, then cooled to 1250-1300℃ at 150℃ / min, held for 1-6 h, and then cooled with the furnace; the pressure is maintained at 20 MPa from room temperature to 1200℃, and at 45 MPa from 1200-1250~1450℃.

10. The high-entropy alloy binder phase gradient cemented carbide tool material according to claim 1 or 2, and the application of the high-entropy alloy binder phase gradient cemented carbide tool material prepared by the method according to any one of claims 3-9 in the preparation of cemented carbide tools.